An SAR autofocus algorithm based on hybrid model

doi:10.7523/j.issn.2095-6134.2016.05.012

Abstract

Abstract:

An SAR autofocus algorithm based on hybrid model is proposed. The hybrid model is a polynomial specially designed for focus filter. The hybrid model consists of two parts. The first part is a fixed-order Taylor polynomial to estimate the low frequency phase errors. The second part is an adaptive-order sinusoidal polynomial to estimate the high frequency phase errors. Through searching the hybrid model parameters, a better focus result is achieved when the phase errors contain more high frequency components. The simulation and experiment on real airborne SAR data demonstrate the validity and effectiveness of the proposed algorithm.

Key words: synthetic aperture radar(SAR), autofocus, high frequency phase error, hybrid model

CLC Number:

TN958

YANG Yang, WANG Yanfei. An SAR autofocus algorithm based on hybrid model[J]. , 2016, 33(5): 656-663.

References

[1] Wahl D E, Eichel P H, Ghiglia D C, et al. Phase gradient autofocus:a robust tool for high resolution SAR phase correction[J]. IEEE Transactions on Aerospace and Electronic Systems, 1994, 30(3):827-835.
[2] 刘月花, 荆麟角. 对比度最优自聚焦算法[J]. 电子与信息学报, 2003, 25(1):24-30.
[3] Li X, Liu G, Ni J. Autofocusing of ISAR images based on entropy minimization[J]. IEEE Transactions on Aerospace and Electronic Systems, 1999, 35(4):1240-1252.
[4] Kragh T J. Monotonic iterative algorithm for minimum-entropy autofocus[C]//Proceedings of 14th Adaptive Sensor Array Processing Workshop (ASAP). Atlanta, 2006.
[5] Wang J F, Liu X Z. SAR minimum-entropy autofocus using an adaptive-order polynomial model[J].IEEE Geoscience and Remote Sensing Letters, 2006, 3(4):512-516.
[6] Morrison R L, Do M N, Munson D C. SAR image autofocus by sharpness optimization:a theoretical study[J]. IEEE Transactions on Image Processing A Publication of the IEEE Signal Processing Society, 2007, 16(9):2309-2321.
[7] Gao Y, Yu W D, Liu Y B, et al. Sharpness-based autofocusing for stripmap SAR using an adaptive-order polynomial model[J]. Geoscience and Remote Sensing Letters, IEEE, 2014, 11(6):1086-1090.
[8] 张双喜, 孙光才, 周峰, 等. 一种基于子孔径自聚焦的高频运动误差估计和补偿方法[J]. 电子与信息学报,2010, 32(12):3013-3017.
[9] Li J C, Wang P B, Chen J, et al. An improved two-step motion compensation method based on raw data[C]//Geoscience and Remote Sensing Symposium (IGARSS), 2015 IEEE International.2015:26-31.
[10] Xiong T, Xing M D, Wang Y, et al. Minimum-entropy-based autofocus algorithm for SAR data using chebyshev approximation and method of series reversion, and its implementation in a data processor[J]. IEEE Transactions on Geoscience and Remote Sensing, 2014, 52(3):1719-1728.
[11] 高阳. 高分辨率机载SAR运动误差估计及自聚焦方法研究[D]. 北京:中国科学院大学, 2014.
[12] 王岩飞. 合成孔径雷达相干目标的分辨力评定[J]. 电子科学学刊, 1996(3):230-235.
[13] Fienup J R, Miller J J. Aberration correction by maximizing generalized sharpness metrics[J]. Journal of the Optical Society of America A, 2003, 20(4):609-620.
[14] 刘碧丹, 韩松, 王岩飞. 图像幅度和值最小化自聚焦算法[J]. 电子与信息学报, 2009, 31(4):768-771.
[15] Schulz T J. Optimal sharpness function for SAR autofocus[J]. Signal Processing Letters, IEEE, 2007, 14(1):27-30.
[16] 武昕伟, 朱兆达. 利用对比度最大化实现SAR图像自聚焦[J]. 现代雷达, 2002, 24(3):20-22.
[17] Cho K M, Hui L H. Autofocus method based on successive parameter adjustments for contrast optimization[P]. US, US7145496. 2006.
[18] 张澄波. 综合孔径雷达:原理, 系统分析与应用[M]. 北京:科学出版社, 1989.
[19] 宋巨龙, 钱富才. 基于黄金分割的全局最优化方法[J]. 计算机工程与应用, 2005, 41(4):94-95.